Improvement in rock-drills



UNITED STATES PATENT OFFICE.

CHARLES COURTOIS, OF VOLCANO, CALIFORNIA.

IMPROVEMENT IN ROCK-DRI L| S.

Specification forming part of Letters Patent No. 40.020, (latedSeptember 22, 1863.

To @ZZ 111720772 it may concern.:

Be it known that I, CHARLES COURTOIS, of Volcano, in the county ofAmador and State of California, have invented a new and usefulImprovement in Rock-Drills and I do hereby declare that the following isafull, clear, and exact description of the same, reference being had tothe accompanying drawings, forming a part of this specification, inWhich- Figure l represents a front elevation of my drill. Fig. 2 is aside elevation of the same. Fig. 3 is a plan or top View of the die forsharpening the drill. Fig. 4 is a vertical cen tral section of the same.

Similar letters of reference indicate corresponding parts in the severalgures.

This invention relates to the peculiar shape of the drill, and to thedie which serves to sharpen the same.

By referring to the drawings it will be noticed that my drill A isconstructed with a stem or shank, a, to which the head b is rigidlyattached. This head is square, and it bevels from the top down towardthe end. The cutting-edge c is about one-third the width ofthe face ofthe square at the top, and the bevel varies according to the hardness ofthe rock.

For soft Work the angle ofthe cutting-ed ge can be made sharper than forhardrock, which requires a blunt or obtuse bevel.

The sides of the head b are concave, as indicated in the die in Fig. 3,wherethe cavity d represents the counterpart of the head of the drill.

By having the sides of the head concave the sharpening of the drill isconsiderably facilitated, and it cut-s much easier and quicker than adrillof the ordinary shape and,further more, my drill will Work twice aslong or more than an ordinary drill before it requires to be sharpened.

B represents the die which I use for sharpening my drill. The cavity din the die corresponds to the shape of the head b, and if the drill isto be sharpened the head is heated and driven down into the die.

The edges of the head are thereby forced into the corners of the cavity,and the faces of the head become concave by the action of the convexsides of the cavity, and at the same time the cutting-edge Will becomesharp, so that it requires but very little hammering when taken from thedie.

By the use of this die the operation of sharpening my drill can beaccomplishedin a short time, and, besides the saving in time by the useof the die, a great savingin steel is effected.

What I claim as new, and desire to secure by Letters Patent, is-.

A drill A, having its head b formed square and beveling with concavesides, and the cutting-edge c about one-third the width of the face cfthe square, as shown and described; also, the employment or use ofthedie B with a cavity, d, corresponding to the shape of the head b, asdescribed, for the purpose of sharpening the drill A.

CHARLES COURTOIS.

Witnesses:

ED. F. TAYLOR, P. F. GovERT.

